The invention relates to an endoscopic insertion apparatus for a spinal column implant system. The spinal column implant system essentially comprises at least one anchoring element, a bone plate (also referred to herein as "vertebra plate") connected to the anchoring element, and at least one connection element for connecting at least two bone plates. A screwing-in tool is provided for screwing the anchoring element into a bone part to secure the bone plate in place and an elongated holding device is provided for holding the bone plate.
Spinal column implant systems of the type mentioned in the introduction can be used to fix various bone parts relative to one another; in particular, such an implant can be used for fixing adjacent vertebrae of the spinal column. Such an implant system is attached to the bone parts using a plurality of insertion instruments. Particularly where restricted access points are involved, for example in endoscopic operations, endoscopic insertion apparatus of the type mentioned in the introduction is used. A holding device associated with the insertion apparatus is used to hold the bone plate and the connection element connected to the bone plate and to introduce them into the body. The screwing-in tool is then used to screw the anchoring element into the bone part, for example. A similar procedure is carried out with a second anchoring element and a bone plate associated therewith. A connection element, for example a connection rod or a connection plate, is then brought up to the bone plate. The connection element is then fixed relative to the bone plate. In particular, a clamp element can be used to fix the connection element to the bone plate. Such a clamp element is generally very small, and hence there is a risk of losing it in the operating area. It is also difficult to position the clamp element properly relative to the bone plate. In order to simplify positioning the clamp element, centering pieces are used. The centering pieces are arranged (for example screwed on or latched) on the unit comprising the bone plate, the anchoring element and the connection element before the clamp element is introduced. Only when the centering piece has been positioned properly is the clamp element introduced using the clamp element guide tool.
In this procedure, it is disadvantageous that the centering piece has to be introduced as an independent instrument after the anchoring element and the bone plate have already been fixed on the bone part. In addition, a separately attached centering piece requires at least one actuation unit with which it can be introduced and removed again.